The lieutenant governor of Alaska abruptly resigned on Tuesday after making unspecified “inappropriate comments,” the state’s governor said.

Gov. Bill Walker, an independent who is in the midst of a tough reelection campaign against Republican and Democratic candidates, announced that Lt. Gov. Byron Mallott had resigned. Valerie Nurr’araaluk Davidson, the state’s health and social services commissioner, was sworn in as Mallott’s replacement.

“It is with profound disappointment and sadness that I accepted the resignation of Lieutenant Governor Byron Mallott,” Walker said in a statement. “Byron recently made inappropriate comments that do not reflect the sterling level of behavior required in his role as Lieutenant Governor.”

Walker said he had learned of the incident on Monday night but declined to give more details.

In a resignation letter, Mallott, a Democrat, said that the comments he made “placed a person whom I respect and revere in a position of vulnerability.”

“I take full responsibility for this action and apologize to, and seek healing for, the person I hurt,” Mallott wrote. “I believe Alaskans have the right to hold their leaders to the highest standards of conduct.”

“Under state law, it is too late for a candidate to withdraw from the ballot; that must happen at least 64 days before the general election,” the statement said. “Under the Alaska Constitution, a vote for governor is considered a vote for the lieutenant governor running with him or her.”

The elections division added that Mallot would “technically be elected along with” Walker, should he win re-election. “However, given Mr. Mallott’s resignation, Governor Walker would be able to appoint a lieutenant governor successor consistent with state statute,” the division said.

It is with profound disappointment that we accepted the resignation of Byron Mallott as Lieutenant Governor. It is our honor to introduce Lt. Governor Valerie Davidson in her new role. We are grateful for her commitment to serve our people and our state with strength and grace. pic.twitter.com/4XrCV9H9kr